Closed captioning (CC) and subtitling are both processes of displaying text on a television, video screen, or other visual display to provide additional or interpretive information. Closed captions typically show a transcription of the audio portion of a program as it occurs (either verbatim or in edited form), sometimes including non-speech elements. Closed caption information can be encoded within a video signal such as in a buffer or in line 21 of the vertical blanking interval (VBI), for example. A drawback of these conventional techniques is that the text represented by the closed caption information only becomes visible with the use of a decoder. Further, certain devices equipped to decode closed caption information may not be equipped to provide upstream diagnostic feedback. These and other shortcomings are addressed by the present disclosure.